There is provided a method of fabricating a semiconductor light emitting device, including: forming a sacrificial layer having a plurality of nanostructures on a growth substrate; forming a protective layer to cover the sacrificial layer; forming a light emitting structure by allowing a first conductive semiconductor layer, an active layer and a second conductive semiconductor layer to be sequentially grown on the protective layer; etching the protective layer to expose the nanostructures; and separating the light emitting structure from the growth substrate by etching the exposed nanostructures, whereby damage and degradation of a light emitting structure at the time of the separation thereof may be prevented.